1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device and a substrate processing apparatus, and more particularly, to a method of manufacturing a semiconductor device, which includes a process of selectively growing a silicon epitaxial film on a source/drain of a substrate used in the production of Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), and a substrate processing apparatus using the same.
2. Description of the Prior Art
With high integration density and high performance of MOSFET, both of the improved substrate characteristics and the miniaturization are required simultaneously. To meet this requirement, the source/drain of the MOSFET are required to have the reduced leakage current and the low resistance. One approach to solving those problems is to selectively growing a silicon epitaxial film on the source/drain.
There are two conventional methods of growing a selective epitaxial film: a method of supplying a film-forming gas and an etching gas simultaneously and a method of supplying a film-forming gas and an etching gas alternately.
In the case of supplying the film-forming gas and the etching gas simultaneously, it is difficult to ensure both the selectivity and the film thickness uniformity. If the selectivity is increased, the uniformity is significantly degraded because the central part of the substrate gets thick, whereas the peripheral part gets thin. On the other hand, if the uniformity is ensured, there is a problem in that the selectivity is degraded and thus a film is also formed on an insulation film. Furthermore, the process control is difficult because process parameters are increased very much, and the film-forming rate is greatly reduced because the etching gas is introduced during the film formation.
Meanwhile, in the case of supplying the film-forming gas and the etching gas alternately, a film-forming step for a film formation only and an etching step for an etching process only are performed. However, in the film-forming step, there is a problem that conditions capable of ensuring the selectivity are narrow, in order to perform the selective growth by using difference of growth start time on the silicon and the insulation film. Furthermore, when removing nuclei formed on the insulation film by using gas having a strong etchability, an etching amount is changed due to the etching dependence caused by difference of the film quality of a polysilicon film on the substrate or a silicon substrate, and thus, some regions are etched more than necessary.
Therefore, in the simultaneously supplying process or the alternately supplying process according to the related art, it is difficult to grow a sufficiently thick epitaxial film while maintaining the selectivity and the film thickness uniformity in the substrate plane.